1. Field of the Invention
The present invention is related to a heat exchanger used in air conditioners and the like.
2. Description of the Prior Art
In an air conditioner comprising an indoor unit and outdoor unit, a heat exchanger 1 of a type, for example, as shown in FIG. 4(A) is mounted in the indoor unit, and a heat exchanger 2 of a type as shown in FIG. 4(B) is mounted in the outdoor unit. Each heat exchanger is comprised of a heat transfer fin unit in which heat transfer coils 4, through which a cooling medium flows, penetrate through a row of multiple heat transfer fins set at a specified fin pitch.
In a typical heat exchanger, two heat transfer fin units configured in this manner are closely adjoined in parallel. For this, it was desirable to develop a heat transfer fin with a smaller number of slits to reduce draft resistance. After examining a variety of configurations, it was discovered that heat transfer efficiency could be maximized with a relatively small number of slits at a certain slit width.
An example of the subject of the present invention is shown in FIG. 3, whereby four relatively wide slits are formed on the surface of a heat transfer fin. In this figure, 31, 32 are two heat transfer fin units which comprise a heat exchanger, 4 is a heat transfer coil, and 61, 62, 63, 64 are four slits formed, in order from the left, on the surface of a heat transfer fin. Each of these slits is pushed out to form a slope. In the diagram, numbering of the same slits formed for each of the other heat transfer coils of heat transfer fin units 31 and 32 is omitted.
Slit 61 is positioned relative to the air flow in front of heat transfer coil 4, while slit 64 is positioned behind the heat transfer coil. Slits 62, 63 are formed between a heat transfer coil 4 and another heat transfer coil 4. This slit configuration is the same for each of the other heat transfer coils of heat transfer fin units 31, 32.
As air flow onto the heat transfer fins of a heat exchanger of this type is created with the intake of air in the direction of the arrow, there will be little air resistance in the center where there are few slots. Consequently, the wind speed will be faster in the center than above or below that area, and the flow of air at the center will also be distributed unevenly. As such, the slits cannot be utilized effectively since air does not make uniform contact with the slits, and the heat exchanging activity of the heat exchanger does not function efficiently.